Malleable bone compositions to deliver demineralized bone particles to osseous defects and effect spinal fusion include carrier based technologies. Conventional carrier based bone particle compositions have employed a patient's own blood as a vehicle in which both demineralized and non-demineralized bone particles are suspended.
Various alternatives to use of blood as a carrier have also been proposed. A composition termed Grafton, described in U.S. Pat. No. 5,073,373, a registered trademark of Osteotech, Inc., is a mixture of demineralized bone particles 1000 microns to 12,000 microns in size. Grafton purports to allow the surgeon to conveniently place allograft bone at the surgical site.
A bone gel and putty produced by dissolving demineralized bone matrix in an aqueous solution at temperatures above 25° C. is described in U.S. Pat. No. 6,576,249. The resulting viscous supernatant is cooled and mixed with non-demineralized or demineralized bone particles to produce a gel or putty-like material. A flowable demineralized bone powder composition with large particle sizes between 0.1 cm to 1.2 cm suspended in a low molecular weight polyhydroxy compound is described in U.S. Pat. No. 5,290,558. Another bone composition including demineralized bone material mixed with a carrier for reconstructing bone or tooth defects is described in U.S. Pat. No. 4,172,128. The carrier is made by adding a mucopolysaccharide to mineralized bone colloidal material. The composition is prepared by dissolving bone or tooth tissue in a solvent forming a colloidal solution. To this is added inert polyhydroxy compounds such as polyuronic acid. Hydrogen or polyvalent metal ions are added to from a gel. The gel is purported to be flowable at temperatures above 35° C. Still another method for making bone putty or gel is described in U.S. Pat. No. 6,030,635. Bone powder is suspended in a carrier consisting of sodium hyaluronate, chitosan, and N, O-carboxymethylchitosan in an aqueous solution. An additional hydrogel is also described. Another bone particle composition including bone meal is described in U.S. Pat. No. 4,191,747 wherein it is advocated that osseous defects be filled with coarsely ground, denatured bone meal freed from fat. The bone meal is mixed with polysaccharide in saline solution and applied to a bone defect.